A strong earthquake (preliminary magnitude of 7.1 later revised to 6.8) has been detected in a remote area of the Aleutian Islands off Alaska, about 1,000 miles west southwest of Anchorage, the U.S. Geological Survey reports.

"A Tsunami Warning is now in effect which includes the coastal areas of Alaska from Unimak Pass, Alaska (80 miles NE of Dutch Harbor) to Amchitka Pass, Alaska (125 miles W of Adak)."

We'll update as the story develops.

Update at 8:15 a.m. ET: Magnitude Lowered.

The USGS now estimates it was a 6.8 magnitude quake.

Update at 8:08 a.m. ET: The local tsunami warning has been canceled. "NO destructive tsunami has been recorded, and NO tsunami danger exists along the coasts of the U.S. west coast states, Alaska, and British Columbia. Local authorities can assume all clear upon receipt of this message," the West Coast and Alaska Tsunami Warning Center says.

Update at 7:25 a.m. ET: USGS just revised its estimate of the quake's depth, to 22.1 miles. Earlier, it put the depth at 6.2 miles.